Monitor Advanced replication

Question

Hi,
we have advanced replication set up between two Master sites, this setup also serves purpose of DR solution as replication sites are in different cities. My question is that in case of disaster, how can we determine that when was the last 'push' we got from the other site...
To elaborate it more...For eg we have Advanced replication between Melbourne and Sydney and 'sydney' goes down..how can we tell (sql query) that when was the last time we got successful 'push' from sydney to Melbourne...
and reasoning for this question is to answer Exec's question that what is the data loss scenario in Sydney..
Thanks
Manu

Answer 1

You can see when the push occurs at source (e.g. Sydney) by running this:
SELECT last_date
FROM dba_jobs
WHERE what LIKE '%dbms_defer_sys.push%';However, if you loose Sydeny this isn't much use ... have you thought about setting up a simple "heartbeat" table which is part of the same replication configuration? We do this with our streams setup, the heartbeat table simply gets a row instered every minute via a scheduler job (or whatever frequency/mechanism you choose) with the current timestamp on the source system, we then replicate this to the target - you can then see on the target the "transaction lag" - i.e. what is the most recent timestamp in the table and thus when we last replicated data over, clearly this wont account for errors occuring for other tables but this will need monitoring seperately.
Thanks
Paul